As above. I have a collection of old M42 primes from film cameras I occasionally use with my D3200. They aren't something I chuck in the bag for walk-about or landscape stuff. Kit lens covers the 35-50 range, and all you are getting from primes is the low f-no, which can be great for close up or portraits to blurr back ground, but probably isn't so important for landscape where your are focusing close on infinity and probably using a high f-no to maximise depth of focus. I would say that for landscape & walk-about a wide-angle zoom, something like a 10-24 would probably be higher up my list than either of the AF primes.
To retrieve my camera from clammy claws of daughter doing her photo-O-Level, and booked to carry on doing her A in it; I have just acquired her a D3100 and 35/18. Studied decision, that combination, but doing the exercises set by her tutor she was starting to rub into the buffers of what she could do with the kit 18-55 on my camera, with still life studies, & portraiture, indoor studio stuff, and demonstrations of things like controlled Depth of Focus and bokah effects.
35mm is the 'standard' angle of view for an APS sized DSLR, equivalent to a 50 on an old film camera, which was what most came with, and was the 'all round' general purpose fixed prime, a lot of us started out with whey-back-when, and a lot of ideas and exercises in more taught photography are based around; hence seemed a logical choice to sacrifice zoom for f-no for her with one.
The little she has done with it (She's only had it a week.. conveniently half term week) has sort of confirmed it was the right thinking, for a 'Learning Lens', and I have to say I was very impressed with it, and half tempted to try and get one of my own.. especially at the price; they do seem to be incredibly good VFM... BUT, I would say its a 'Learning Lens', which could still make it very useful, and a lot of fun to play with and experiment.. but I doubt that it will take you very far in your Landscape photo, other than breaking 'zoom dependency' and making you move your feet to frame your subject and take a bit more time to consider other angles.